September 16, 2009

"Transparent and red ZnO – Which defect is responsible for the color?"

Professor Marc Weber
Washington State University


Abstract:

Zinc oxide (ZnO) is a wide bandgap transparent semiconductor with tremendous potential in a broad range of applications. After more than 6 decades of research many obstacles remain. The largest challenge is to fabricate p-type material, an essential step towards electronic applications. I will discuss our recent work on this material and our view of oxygen vacancies and hydrogen impurities. Optical measurements and positron annihilation spectroscopy were applied to ZnO annealed in a range of conditions. Under oxygen poor conditions (sometimes referred to as zinc rich) ZnO may turn red. Methods to indirectly detect positively charged oxygen vacancies and to manipulate the hydrogen content will be discussed. A consistent, but controversial, picture emerges. Hydrogen occupying oxygen vacancies is the most likely defect responsible for the red color.

 

© 2009 The University of Texas at Arlington | Department of Physics, Box 19059, Arlington, Texas 76019
Phone 817.272.2266 | Fax 817.272.3637
Questions about this site? Email: Webmaster